Method of making a clear, stable aqueous mouthwash solution and the solution made by that method for the enhancement of cells of the oral cavity and the remineralization of teeth

ABSTRACT

A solutions for optimizing the environmental conditions within the human oral cavity is disclosed which enhances the functioning of cells of the oral cavity and promotes remineralization of teeth. These solutions are effective in treating and preventing caries and periodontal disease and reducing mouth odor and are easily and safely used by the lay population. A method of making the solutions which totally prevents the formation of calcium phosphate crystals, for example hydroxyapatite, is disclosed.

This application is a continuation-in-part of application Ser. No.286,107 filed July 22, 1981, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a method for making a solution containing acomposition for optimizing the environmental conditions within the humanoral cavity and more particularly to a clear, stable aqueous solutioncontaining a composition for remineralizing teeth and for improving thefunction of the oral leucocytes and to a method of preparing the same.

It has been heretofore known to utilize various solutions to aid inremineralizing teeth that have caries lesions in them and to enhancemineralization of normal teeth so they are much less likely to getcaries. Because of the presence of calcium ions and phosphate ions inthese solutions and the affinity of these ions for each other with theaccompanying precipitation of calcium phosphate salt from solution, itis necessary to maintain these materials in separate containers untilshortly prior to use. This requirement substantially renders the conceptimpractical as an item for consumer sales because it necessitates mixingproportionate amounts of each ingredient immediately prior to use. Thepublic generally avoids products having this type of requirement. (See"Continuing Evaluation of the Use of Fluorides" AAAS Selected Symposium11, Published by Westview Press, Inc., 5500 Central Ave., Boulder, Colo.80301.)

U.S. Pat. No. 4,024,237, discloses chemical formulations (fourillustrative formulations are included) which are comprised of non-toxicingredients which favor and promote oral leucocyte function, includinglocomotion, phagocytosis and protoplasmic function resulting in thecontrol and kill of bacteria (col. 3, lines 12-16). It is proposed thatoral diseases such as periodontal disease and perhaps dental caries canbe controlled and treated, especially early periodontal disease (col. 3,lines 16-21). The compositions of this patent contain non-toxicingredients for four principal purposes:

(1) Maintaining a colloidal and viscous environment within the oralcavity which favors and promotes oral leucocyte locomotion,phagocytosis, and bacterial kill.

(2) Providing the oral leucocytes with a suitable source of energy whenneeded.

(3) Providing and maintaining a balanced ionic environment which favorsand promotes locomotion, phagocytosis, and bacterial kill.

(4) Maintaining substantially a physiological pH in order to promoteleucocyte functions while avoiding other tissue and cell injury (col. 3,lines 23-25).

The patent contains descriptions of studies which show that use producedincreased numbers of healthy oral leucocytes which can be harvested,enhanced the number of oral leucocytes which showed bacterial killingability, and produced a dramatic improvement of a periodontal disease(gingivitis) in subjects who used a formulation of the patent applied bythemselves (col. 7 to col. 11, line 56).

U.S. Pat. No. 4,283,385 discloses dentrifrice preparations havingincorporated therein ethylenediamine tetraacetic acid and the sodiumsalts thereof. Also employed in the dentrifrice are abrasives such ascalcium, carbonate and various calcium phosphates. These are employedgenerally in amounts of from about 5% to about 60% by weight. The minoramount of ethylenediamine tetracetic acid brings about the inhibition ofthe inactivation of soluble fluoride by the calcium containingabrasives.

U.S. Pat. Nos. 4,183,915 and 4,177,258 disclose a stable aqueousremineralizing solution having a source of calcium ions and phosphateions sufficient to effect remineralization, a fluoride providing agentand a phosphorous containing antinucleating agent which absorbs onto aspherical nucleated particle of hydroxyapatite as it forms and entirelyblocks crystal growth. The stable remineralizing solution is prepared byadding the calcium ion and phosphate ion sources to water and loweringthe pH to keep the solution clear.

An article by Meyer and Nancollas entitled "The Influence ofMulti-Dentate Organo-Phosphonates on the Crystal Growth ofHydroxyapatite." Calc. Tiss. Res., 13:295-303 discusses the rate ofcrystal growth of hydroxyapatite seed crystals in stable supersaturatedsolutions of calcium phosphate in the presence of organic phosphorates.The most effective of the phosphorates, N, N, N¹, N¹ethylenediamine-tetra (methyline phosphonic acid) is structurallysimilar to ethylenediamine tetraacetic acid and would also be expectedto be a good chelating agent for calcium ions situated at crystalsurfaces.

It is an important consideration when dealing with prophylactic andtherapeutic compositions for treatment of the human oral cavity, thatusers of these compositions can apply them at their own conveniencewithout an appreciable amount of preparatory effort or the supervisionof medically trained personnel. Further, the composition must benon-toxic in substantially all amounts if the objective is to make thesecompositions freely available to the general public.

It is therefore an object of this invention to provide an improvedmethod of preparing a solution containing a composition capable of beingstored in a single container, for optimizing the environmentalconditions within the human oral cavity and the solution made by a saidmethod.

It is another object of this invention to provide an improved mouthwashsolution and a method of preparing said solution maintainable as a onebottle solution capable of remineralizing caries lesions in the teethand mineralizing normal teeth to prevent caries from forming.

It is a further object of this invention to provide an improved solutionand a method of preparing said Composition maintainable as a one bottlesolution to stimulate the white cells present in the oral cavity to actas a protective mechanism to prevent periodontal disease or treat it ifalready in existence.

It is still a further object of this invention to provide an improved amethod of preparing said solution capable of achieving the advantages ofboth of the two previously stated objectives.

It is a still further object of this invention to provide an improvedmethod of preparing an oral lavage solution which reduces or eliminatesmouth odor.

SUMMARY OF THE INVENTION

The foregoing objects and others, which will become apparent from thefollowing description are accomplished in accordance with the invention,generally speaking, by providing a method of making a clear aqueousmouthwash solution capable of remineralizing caries lesions in teeth byforming an aqueous solution containing a source of calcium ions and achelating agent for calcium ions, causing the chelation of at least 50%of the calcium ions, and subsequently adding a source of phosphate ionsto the aqueous solution. The invention also contemplates the compositionprepared by the above stated process for remineralizing caries lesionsand, in addition, for optimizing the environmental conditions within thehuman oral cavity.

DETAILED DESCRIPTION OF THE INVENTION

Thus, the invention contemplates a method of preparing the compositionfor remineralizing teeth; for enhancing the action of leucocytes or foraccomplishing both of these functions. As a result of the promotion ofthe normal physiology and responses of the tissues and cells of the oralcavity, locally produced malodor is materially reduced or eliminated.

The method of the invention contemplates the steps of making a clearaqueous mouthwash solution by initially forming a solution in water of asource of calcium ions and a chelating agent for calcium ions wherein atleast 50% of the calcium ions are chelated prior to the addition of asource (phosphate containing compound) of phosphate ions. By bringingabout the chelation of at least 50% of the calcium ions, theprecipitation of calcium phosphate (hydroxyapatite) from the solution isavoided. This invention contemplates the chelation of 100% of thecalcium ions present in the solution. The percentage of calcium ionsthat are chelated can be controlled by controlling the ratio of themoles of chelating agent per mole of the calcium ion source. That is,for each mole of the calcium compound present in the aqueous solution asthe source of calcium ions, 0.5 to 1.05 moles of chelating agent areused. The excess amount of chelating agent insures that all the calciumions are chelated. While higher amounts of chelating agent can beemployed, it is not necessary to do so from an economic viewpoint.

Subsequent to the chelation step, the phosphate containing compound andother desirable reagents such as fluoride containing and sodiumcontaining compounds, in addition to others, which will become apparenthereinafter, may be added.

The chelating agent is one having an affinity for calcium and includesedetic acid (also known as EDTA, ethylenedinitrilo - tetraacetic acid,ethylene diamine tetraacetic acid), glyceric acid, tartaric acid, thesodium, potassium calcium and zinc salts of the above, and the like. Asmentioned above, the chelating agent, or combination of chelating agentsis employed in an amount such that at least 50% of the calcium ions arechelated thus preventing calcium phosphate salt from precipating fromsolution.

As examples of useful compounds as sources of calcium ions, mention maybe made of calcium chloride, calcium carbonate, calcium fluoride,calcium chloride hexahydrate, calcium chloride dihydrate, and the like.

As examples of useful compounds as phosphate ion sources, mention may bemade of monosodium dihydrogen phosphate, monosodium dihydrogen phosphatemonohydrate, disodiummonohydrogen phosphate, monopotassium dihydrogenphosphate, and the like.

The remineralizing agent is made up of salts that will provide calcium(Ca) ions and phosphate (PO ) ions and in addition fluoride (F) ions andsodium (Na) ions when in an aqueous solution.

An example of useful reagents that will contribute the necessary ions,mention may be made of calcium chloride, calcium fluoride, sodiumfluoride, sodium chloride, disodiummonohydrogen phosphate, monopotassiumdihydrogen phosphate and the like.

The salts are employed in amounts such that for each 100 parts of volumeof aqueous solution, the required ions are present in the following (inparts by weight):

    ______________________________________                                        Calcium       0.005 to 0.09                                                   Phosphate     0.005 to 0.09                                                   Fluoride      0.001 to 0.01                                                   Sodium         0.1 to 0.5                                                     ______________________________________                                    

By "effective amount of remineralizing agent" is meant an amount whenused in accordance with this invention which will bring about theremineralizing of teeth having caries lesions, or the mineralizing ofnormal teeth to prevent caries from forming by utilizing a mouthwash(lavage) having the various components in the amounts set forth above,this is achieved.

The leucocyte enhancing agent is a composition containing at leasteffective amounts of a non-toxic mixture of ingredients for: (1)maintaining a colloidal and viscous environment of the oral cavity whichfavors and promotes oral leucocyte locomotion, phagocytosis andbacterial kill; (2) providing the oral leucocytes with a suitable sourceof energy when needed; (3) providing and maintaining a balanced ionicenvironment which favors and promotes locomotion, phagocytosis andbacterial kill; and (4) maintaining the pH substantially the same as inthe oral cavity, e.g., 5.5 to 9.0, but preferably as close tophysiological pH as possible. The composition may, but not necessarily,also contain non-toxic ingredients for providing a negative chargepotential in the oral cavity to reduce clustering of leucocytes and toeliminate agglutination and precipitation of protoplasmic particles.

As examples of useful reagents for maintaining the requisite colloidaland viscous environment, mention may be made of the dextrans, especiallythose having molecular weights ranging from between 15,000 to 40,000,000Daltons, preferably those from about 60,000 to 90,000 Daltons; celluloseand hydroxyethyl cellulose; polyvinylpyrrolidone; gelatin, hydroxyethylstarch, etc.

As examples of energy-providing reagents, mention may be made ofcarbohydrates such as glucose, sucrose, and fructose; phosphorylatedsugar intermediates such as glucose-6-phosphate, fructose-6-phosphatenon-phosphorylated sugar intermediates such as salts, preferably alkalimetal salts (e.g., sodium, potassium or lithium salts) of pyruvic,lactic, acetic acid, or citric acid, etc., and metabolizable fats andproteins.

As examples of useful reagents for providing a properly balanced ionicenvironment, mention may be made of inorganic salts such as sodiumchloride, potassium chloride, calcium chloride, magnesium chloride;magnesium sulfate; monopotassium dihydrogen phosphate, monosodiumdihydrogen phosphate, dipotassium monohydrogen phosphate, disodiummonohydrogen phosphate; sodium bicarbonate, etc.

As examples of reagents for maintaining the pH within the desired range,mention may be made of phosphate buffers, CO₂ -bicarbonate buffer, trisbuffers, glycylglycine buffer, etc.; the CO₂ -bicarbonate buffer beingpreferred.

As examples of useful ingredients for proving a negative chargepotential, mention may be made of heparin, chrondroitin sulfate; andother polyanionic polysaccharides.

The effective amounts of the above mentioned four classes of ingredientsmay be readily determined empirically by those skilled in the art ofsampling the formulation and then examining under the microscopeleucocytes taken from the oral cavity to determine if they are viable,being capable of healthy protoplasmic flow, locomotion and phagocytosisand bacterial kill after application of the composition. By simple androutine analysis, necessary adjustments in the formulation may be madeto achieve optimum results.

In such a manner, we have determined the preferred ranges of ingredientsset forth in the following table, it being appreciated that beneficialresults may also be obtained by employing lesser or greater amounts thanthose recited.

                  TABLE                                                           ______________________________________                                                    Parts by Weight per 100                                                       Parts by Volume of Aqueous                                        Ingredients Solution                                                          ______________________________________                                        1.           0.50 to 10.0                                                     2.          0.10 to 3.0                                                       3.          0.26 to 5.2                                                       4.          0.015 to 1.5                                                      ______________________________________                                    

The compositions in accordance with this invention may also containtherapeutic concentrations of zinc as zinc salts, such as, zincchloride, zinc sulfate, zinc gluconate and the zinc salts of thechelating agents, mentioned above. Zinc has a stabilizing effect on thehydroxyapatible structure of the tooth, increasing hardness anddecreasing solubility rendering the tooth more resistent to cariesformation. Non-therapeutic reagents, which perform specifically desiredfunctions may also be included, such as flavoring and/or effervescingingredients, e.g. citric acid; preservatives, such as benzoic acid,paraamino-benzoic acid or their potassium or sodium salts;anti-oxidants, colorants, viscous reagents, solvents and the like.

For optimum effectiveness, the prophylactic compositions of thisinvention should be retained in solution in the oral cavity for at leastthirty and preferably at least sixty seconds. Since the compositions arecompletely non-toxic, they need not be expectorated, but may beswallowed. This important aspect of the invention permits theprophylactic compositions to be employed at any time, e.g., inrestaurants, or any other public place and/or while the individual is intransit. The mouthwash initiates action as soon as it is taken in themouth.

For optimum effectiveness, treatment should be repeated at least uponarising, after eating, smoking, drinking high concentration alcoholicbeverages, and before going to sleep. An important feature of thepresent invention is that the compositions are completely non-toxic, andhence, may be taken appreciably more often, if desired. It will beappreciated that lesser than optimum treatment will provide benefitsaccordingly.

The invention is further illustrated by the following examples in whichall weights, specified in grams are per 100 cc of aqueous solution:

EXAMPLE 1 Mineralizing Solution with Chelating Agent

Preparation of 100 cc of mineralizing solution;

About 80 cc of distilled, deionized water is placed in a 150 cc beaker,and a magnetic stirring bar is placed in the beaker.

The pH is adjusted to 7.8 using sodium hydroxide (NaOH) and a pH meter.

About 0.175 gm edetic acid and about 0.05 gm NaOH are added to thebeaker, and the solution is heated to approximately 60° C. and held atthat temperature and stirred for 15 minutes. A clear solution results.

The solution is cooled to below 20°C. and the pH is adjusted to 8.0using NaOH and a pH meter.

About 0.1192 gm calcium chloride hexahydrate (CaCl₂ -6H₂ O) is added andstirred, and NaOH is added with stirring until the solution has a pH ofbetween 8 and 10.

The following chemicals are then added, with stirring, in sequence:

0.0011 gm NaF (Sodium fluoride)

0.5592 gm NaCl (sodium chloride)

0.056 gm NaH₂ PO₄.H₂ O (monosodium dihydrogen phosphate monohydrate)

The pH is then adjusted to between 7.5 to 8.0, with 7.8 being optimum,with NaOH.

The volume is adjusted to 100 cc with distilled, de-ionized water.

The solution prepared by using the above 8 steps has remained clear for6 months and held a pH of 7.79 for that time.

The aforementioned solution is the basic mineralizing solution. Largervolumes of the solution are produced simply by scaling up all theingredients.

EXAMPLE 2 Mineralizing Solution with Chelating Agent and Oral Cell(leucocyte) Enhancing Agent

This formulation process is expanded to produce the combinedmineralizing solution and oral tissue enhancing solution. The previouslydescribed seven steps are repeated, and in addition, the followingchemicals are added, with stirring, in sequence:

sodium bicarbonate--7.743 gm

potassium chloride--0.061 gm

magnesium sulfate .7H₂ O--0.051 gm

D-glucose--1.695 gm

hydroxyethyl starch or dextran--2.0 to 8.50 gm

The final volume is adjusted to 100 cc with distilled-deionized water,and the pH is adjusted to 7.5 to 8.0, with 7.8 being optimal, with NaOH.

EXAMPLE 3 Remineralizing Agent plus Chelating Agent

The procedure of Example 1 is repeated but instead of the reagents andquantities as used therein, the following are used:

    ______________________________________                                        calcium chloride        0.0654 gm                                             sodium fluoride         0.0109 gm                                             disodiummonohydrogen phosphate                                                                        0.0577 gm                                             edetic acid             0.172 gm                                              sodium chloride         0.5592 gm                                             ______________________________________                                    

EXAMPLE 4 Remineralizing Agent plus Chelating Agent

The procedure of Example 1 is repeated but instead of the reagents andquantities as used therein, the following are used:

    ______________________________________                                        calcium chloride        0.0654 gm                                             sodium fluoride         0.0109 gm                                             disodiummonohydrogen phosphate                                                                        0.0577 gm                                             glyceric acid           0.0624 gm                                             sodium chloride         0.5592 gm                                             ______________________________________                                    

EXAMPLE 5 Remineralizing Agent plus Chelating Agent

The procedure of Example 1 is repeated but instead of the reagents andquantities as used therein, the following are used:

    ______________________________________                                        calcium chloride        0.0654 gm                                             sodium fluoride         0.0109 gm                                             disodiummonohydrogen phosphate                                                                        0.0577 gm                                             edetic acid             0.086 gm                                              glyceric acid           0.0312 gm                                             sodium chloride         0.5592 gm                                             ______________________________________                                    

EXAMPLE 6 Remineralizing Agent plus Leucocyte Enhancing Agent plusChelating Agent

The procedure of Example 2 is repeated but instead of the reagents andquantities as used therein, the following are used:

    ______________________________________                                        calcium chloride        0.047 gm                                              sodium chloride         2.373 gm                                              sodium fluoride         0.010 gm                                              monopotassium dihydrogen                                                                              0.029 gm                                              phosphate                                                                     dextran                 8.500 gm                                              D-glucose               1.695 gm                                              sodium bicarbonate      7.743 gm                                              potassium chloride      0.061 gm                                              magnesium sulfate 7H.sub.2 O                                                                          0.051 gm                                              edetic acid             0.124 gm                                              ______________________________________                                    

EXAMPLE 7 Remineralizing Agent plus Leucocyte Enhancing Agent plusChelating Agent

The procedure of Example 2 is repeated but instead of the reagents andquantities as used therein, the following are used:

    ______________________________________                                        calcium chloride        0.047 gm                                              sodium chloride         2.373 gm                                              sodium fluoride         0.010 gm                                              monopotassium dihydrogen                                                                              0.029 gm                                              phosphate                                                                     dextran                 8.500 gm                                              D-glucose               1.695 gm                                              sodium bicarbonate      7.743 gm                                              potassium chloride      0.061 gm                                              magnesium sulfate 7H.sub.2 O                                                                          0.051 gm                                              glyceric acid           0.045 gm                                              ______________________________________                                    

EXAMPLE 8 Remineralizing Agent plus Leucocyte Enhancing Agent plusChelating Agent

The procedure of Example 2 is repeated but instead of the reagents andquantities as used therein, the following are used:

    ______________________________________                                        calcium chloride        0.047 gm                                              sodium chloride         2.373 gm                                              sodium fluoride         0.010 gm                                              monopotassium dihydrogen                                                                              0.029 gm                                              phosphate                                                                     dextran                 8.500 gm                                              D-glucose               1.695 gm                                              sodium bicarbonate      7.743 gm                                              potassium chloride      0.061 gm                                              magnesium sulfate 7H.sub.2 O                                                                          0.051 gm                                              edetic acid             0.062 gm                                              glyceric acid           0.023 gm                                              ______________________________________                                    

The systematic use of a mouthwash in accordance with the above examplesresults in the establishment of an improved environment within the humanoral cavity resulting in the remineralizing of teeth and improvedfunction of oral leucocytes, aiding in the preservation of cellular andtissue elements therein, together with the prevention of periodontaldisease and dental caries, and the reduction or elimination of mouthodor.

We claim:
 1. A method of making a clear, stable, aqueous mouthwashsolution capable of remineralizing caries lesions in teeth whichcomprises forming a stable, aqueous solution containing a source ofcalcium ions in an amount therapeutically effective to produce saidremineralizing of caries lesions in teeth and a chelating agent forcalcium ions, causing the chelation of at least 50% of the calcium ionsby preparing a clear, aqueous solution of the chelating agent having analkaline pH, then adding the source of calcium to said clear, aqueoussolution of the chelating agent, and then adjusting the pH to analkaline pH, and subsequently adding a source of phosphate ions to saidaqueous solution.
 2. The method of claim 1 wherein from 50 to 100percent of the calcium ions are chelated.
 3. The method of claim 2wherein 100% of the calcium ions are chelated.
 4. The method of claim 1wherein the chelating agent is selected from the group consisting ofedetic acid, glyceric acid, tartaric acid and the sodium potassiumcalcium and zinc salts thereof.
 5. The method of claim 4 wherein thegroup member is edetic acid.
 6. The method of claim 1 wherein from about0.5 mole to about 1.05 mole of chelating agent is present in the aqueoussolution per mole of the source of calcium ions present.
 7. The methodof claim 1 wherein a molar excess of chelating agent is present in theaqueous solution with respect to the source of calcium ions present. 8.The method of claim 1 wherein, subsequent to the addition of the sourceof phosphate ions to the aqueous solution, a leucocyte enhancing agentis added.
 9. The method of claim 1 wherein subsequent to the step ofcausing the chelation of calcium ions, a source of fluoride ions isadded to the aqueous solution.
 10. The method of claim 1 wherein the pHof the final aqueous solution is adjusted to from 7.8 to
 8. 11. Themethod of claim 8 wherein the leucocyte enhancing agent is a non-toxicmixture of effective amounts of: (1) at least one compound selected fromthe group consisting of dextran, cellulose ethers, polyvinylpyrrolidoneand gelatin for maintaining a colloidal and viscous environment withinthe oral cavity which favors and promotes oral leucocyte locomotion,phagocytosis and bacterial kill; (2) at least one compound selected fromthe group consisting of carbohydrates, fats and proteins to provide asource of energy for said oral leucocytes; (3) an inorganic saltproviding and maintaining a balanced ionic environment which favors andpromotes locomotion, phagocytosis and bacterial kill; and (4) at leastone compound selected from the group consisting of phosphate buffers,carbon dioxide-bicarbonate buffers, tris buffers and glycylglycinebuffers for maintaining substantially a physiological pH to promoteleucocyte functions while avoiding other tissue and cell injury.
 12. Aclear aqueous mouthwash solution capable of remineralizing carieslesions in teeth prepared by the process of claim
 1. 13. The mouthwashsolution as set forth in claim 12 to which a leucocyte enhancing agentis added.
 14. The mouthwash solution as set forth in claim 12 to which asource of flouride ions is added.
 15. The mouthwash solution as setforth in claim 13 wherein the leucocyte enhancing agent is a non-toxicmixture of effective amounts of: (1) at least one compound selected fromthe group consisting of dextran, cellulose ethers, polyvinylpyrrolidoneand gelatin for maintaining a colloidal and viscous environment withinthe oral cavity which favors and promotes oral leucocyte locomotion,phagocytosis and bacterial kill; (2) at least one compound selected fromthe group consisting of carbohydrates, fats and proteins to provide asource of energy for said oral leucocytes; (3) an inorganic saltproviding and maintaining a balanced ionic environment which favors andpromotes locomotion, phagocytosis and bacterial kill; and (4) at leastone compound selected from the group consisting of phosphate buffers,carbon dioxide-bicarbonate buffers, tris buffers and glycylglycinebuffers for maintaining substantially a physiological pH to promoteleucocyte functions while avoiding other tissue and cell injury.
 16. Themethod according to claim 1 wherein said alkaline pH of said clear,aqueous solution of said chelating agent is at least 7.8.
 17. The methodaccording to claim 16 wherein the pH of said clear, acqueous solution ofsaid chelating agent to which said calcium source is added is adjustedbetween 8 and 10.